1. Field of the Invention
The present invention relates to a method for preparing a solid titanium catalyst for olefin polymerization, which can provide a solid catalyst having high activity, and by using said catalyst polyolefin with high stereoregularity can be produced easily compared with the conventional method.
2. Description of the Related Art
Many titanium-based catalysts for olefin polymerization containing magnesium and process for producing such catalyst have been reported in the art related to the present invention. For instance, some methods which obtain a magnesium solution by reacting a magnesium compound with an electron donor such as an alcohol, amine, ether, ester or a carboxylic acid in the presence of hydrocarbon solvent are disclosed, and among them specifically the use of an alcohol is disclosed in U.S. Pat. Nos. 4,330,649 and 5,106,807, and Japanese Laid-Open Sho-58-83006, etc. Also, U.S. Pat. Nos. 4,315,874, 4,399,054 and 4,071,674 disclose a method for preparing a magnesium solution. As for ether compound, tetrahydrofuran, which is one of cyclic ether, has been variously used for a magnesium chloride compound such as in U.S. Pat. No. 4,482,687, as an additive for a cocatalyst such as in U.S. Pat. No. 4,158,642 and as a solvent such as in U.S. Pat. No. 4,477,639.
Further, U.S. Pat. Nos. 4,347,158, 4,422,957, 4,425,257, 4,618,661 and 4,680,381 disclose a method for preparing a catalyst comprising the steps of adding a Lewis acid compound such as aluminum chloride to a magnesium chloride support and grinding the mixture.
As shown above, there have been many catalysts for olefin polymerization and various polymerization methods using the same reported so far, however those methods need to be improved further in view of catalyst activity and stereoregularity of the polymer produced. Therefore, there are still needs for further researches to increase catalyst activity for reducing the production cost, and to improve polymer properties such as stereoregularity by improving the catalyst used in the polymerization.